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- Microbial degradation of 17β -estradiol and 17α -ethinylestradiol followed by a validated HPLC-DAD methodPublication . Ribeiro, Ana R.; Carvalho, Maria F.; Afonso, Carlos M. M.; Tiritan, Maria E.; Castro, Paula M.L.This work aimed at studying the biodegradation of two estrogens, 17agr -estradiol (E2) and 17β -ethinylestradiol (EE2), and their potential metabolism to estrone (E1) by microbial consortia. The biodegradation studies were followed by High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD) using a specifically developed and validated method. Biodegradation studies of the estrogens (E2 and EE2) were carried out with activated sludge (consortium A, CA) obtained from a Wastewater Treatment Plant (WWTP) and with a microbial consortium able to degrade recalcitrant compounds, namely fluorobenzene (consortium B, CB). E2 was more extensively degraded than EE2 by CA whereas CB was only able to degrade E2. The addition of acetate as a supplementary carbon source led to a faster biodegradation of E2 and EE2. E1 was detected as a metabolite only during the degradation of E2. The 16S rRNA gene sequence analyses of strains recovered from the degrading cultures revealed the presence of the genera Pseudomonas, Chryseobacterium and Alcaligenes. The genera Pseudomonas and Chryseobacterium were retrieved from cultures supplied with E2 and EE2, while the genus Alcaligenes was found in the presence of E2, suggesting that they might be involved in the degradation of these compounds.
- Chiral analysis of pesticides and drugs of environmental concern: biodegradation and enantiomeric fractionPublication . Maia, Alexandra S.; Ribeiro, Ana R.; Castro, Paula M. L.; Tiritan, Maria ElizabethThe importance of stereochemistry for medicinal chemistry and pharmacology is well recognized and the dissimilar behavior of enantiomers is fully documented. Regarding the environment, the significance is equivalent since enantiomers of chiral organic pollutants can also differ in biodegradation processes and fate, as well as in ecotoxicity. This review comprises designed biodegradation studies of several chiral drugs and pesticides followed by enantioselective analytical methodologies to accurately measure the enantiomeric fraction (EF). The enantioselective monitoring of microcosms and laboratory-scale experiments with different environmental matrices is herein reported. Thus, this review focuses on the importance of evaluating the EF variation during biodegradation studies of chiral pharmaceuticals, drugs of abuse, and agrochemicals and has implications for the understanding of the environmental fate of chiral pollutants.
- Microbial degradation of pharmaceuticals followed by a simple HPLC-DAD methodPublication . Ribeiro, Ana R.; Goncalves, Virgínia M.F.; Maia, Alexandra S.; Carvalho, Maria F.; Castro, Paula M.L.; Tiritan, Maria E.The biodegradation of five pharmaceutical ingredients (PIs) of different therapeutic classes, namely antibiotics (trimethoprim, sulfametoxazole and ciprofloxacin), anti-inflammatory (diclofenac) and anti-epileptic (carbamazepine), by two distinct microbial consortia, was investigated. For the monitoring of biodegradation assays, a simple HPLC-DAD (High Performance Liquid Chromatography – Diode Array Detector) method was developed and validated. The separation of the target pharmaceuticals was performed using an environmental friendly mobile phase in a gradient mode of 0.1% triethylamine (TEA) in water acidified at pH 2.23 with trifluoroacetic acid (TFAA) and ethanol as organic solvent. The method revealed to be selective, linear and precise in the range of 1.0 to 30.0 μg/mL for all PIs. Biodegradation assays were performed using activated sludge and a bacterial consortium (able to degrade fluoroaromatic compounds) supplemented with the target PIs at a final concentration of 25 μg/mL. The results revealed that activated sludge removed the target compounds more efficiently than the bacterial consortium.
- Chiral pharmaceuticals in the environmentPublication . Ribeiro, Ana R.; Castro, Paula M. L.; Tiritan, Maria E.Many pharmaceutical pollutants are chiral, existing in the environment as a single enantiomer or as mixtures of the two enantiomers. In spite of their similar physical and chemical properties, the different spatial configurations lead the enantiomers to have different interactions with enzymes, receptors or other chiral molecules, which can give diverse biological response. Consequently, biodegradation process and ecotoxicity tend to be enantioselective. Despite numerous ongoing research regarding analysis and monitorization of pharmaceutical ingredients in the environment, the fate and effects of single enantiomers of chiral pharmaceuticals (CP) in the environment are still largely unknown. There are only few chiral analytical methods to accurately measure the enantiomeric fraction (EF) in environmental matrices and during biodegradation processes. Furthermore, the ecotoxicity studies usually consider the enantiomeric pair as unique compound. We reviewed the current knowledge about CP in the environment, as well as the chiral analytical methods to determine the EF in environmental matrices. The degradation and removal processes of CP of important therapeutic classes, usually detected in the environment, and their toxicity to aquatic organisms were also reviewed. On the other hand, this review demonstrate that despite the great importance of the stereochemistry in pharmaceutical science, pharmacology and organic chemistry, this is normally neglected in environmental studies. Therefore, CP in the environment need much more attention from the scientific community, and more research within this subject is required.